RFID is used to uniquely identifying items using radio waves. A typical RFID system comprises an RFID tag and an RFID reader (also referred to as a reader, or a reader device). The RFID reader sends an interrogating signal (e.g., a radio-frequency signal) to the RFID tag, and the RFID tag responds with its unique information. RFID systems may operate at various frequency ranges, e.g., a low frequency (LF) range between 125 KHz and 134 KHz, a high frequency (HF) of 13.56 MHz, or an ultra-high frequency range between 856 MHz and 928 MHz. Various industry standards exist for RFID communication, e.g., ISO 15693, ISO 18000, and ISO 24730.
Near-field communication (NFC) is a subset of the RFID communication and operate at the same frequency (e.g., 13.56 MHz) as HF RFID readers and tags. Various standards for NFC exists, such as ISO/IEC 14443, ISO/IEC 18092, and ISO/IEC 21481. While RFID system may work for distances up to hundreds of meters, near-field communication typically works at a short distance, e.g., a few centimeters. Due to its short read range and the security associated with such a short communication distance, NFC systems have been used in applications such as contactless payment, electronic ID card, and electronic keycard.